What does non-repudiation in asymmetric encryption provide?

• A. The ability to encrypt multiple times
• B. The inability to deny a previous action
• C. The requirement of a digital signature
• D. The safety of symmetric keys

Answer: (B)

Non-repudiation in asymmetric encryption is a crucial security principle that ensures that a party cannot deny the authenticity of their signature on a document or a message. This capability is fundamentally tied to the way asymmetric encryption works—using a pair of keys: a public key and a private key. When a sender signs a message with their private key, it can be verified by anyone who has access to the corresponding public key, providing clear evidence that the specific sender endorsed that message.

This mechanism prevents a sender from later claiming they did not send the message or take some action, thus establishing accountability. In legal and transactional contexts, this verification process is vital, as it ensures that all parties can trust the origins of the communications and transactions, making it possible to hold individuals accountable for their actions.

The other options, while related to cryptography, do not capture the essence of non-repudiation. Encrypting multiple times (first choice) does not pertain to the idea of accountability, a digital signature (third choice) is a part of the mechanism but does not define non-repudiation alone, and the safety of symmetric keys (fourth choice) addresses key management and security, not the accountability of actions taken by individuals.